1x21 Snowball in Hell
First Aired: Feb. 18, 1967 on CBS
Summary: A former prison guard, Gerard Sefra, has acquired an unstable explosive that is sensitive to high temperatures. He stores it at the prison he once worked at and the IMF have to cause a breakdown in the refrigerator unit to get him to move it to a hospital where they can make the switch.
Main Characters in this Episode
- Goof (factual errors): The script misstates the properties of Cesium-138, possibly deliberately, to prevent information about a hazardous material from being disseminated publicly. First of all, Cesium, regardless of its isotope, has a uniform melting temperature of 28.5 °C (83.3 °F), not 21.1 °C (70 °F) as stated by Barney during the briefing. It will burn, but not explode, when exposed to oxygen or air. It will, however, explode in water. Either reaction occurs whether it is in solid or liquid form, meaning that the requirement for keeping the metal cool is a plot hole as well.
- Goof (factual errors): Although most isotopes of Cesium are radioactive to some degree (Cesium-133 is stable), none of the isotopes have any weapons applications. It is used as a radiation source in laboratories, in the petroleum industry, electronic devices and, perhaps most famously, in atomic clocks (the oscillation period of the cesium-133 atom is now used to define the standard second). Cesium clocks also regulate timing for cell phone networks and internet data flow.
- First episode to use colour head shots of Barney Collier and Willie Armitage in the I.M.F. dossier.
- The title is based on the expression "A snowball's chance in hell" which is an idiom of improbability just like "It will happen when pigs fly".